Retention Rate
Retention rate will be described as the proportion of randomized participants retained the end of the study out of the total number of randomized participants.
Joint-Specific Adverse Events
The number of joint-specific adverse events will be recorded. Joint-specific adverse events are determined as participant not attending an exercise session and/or ceasing participation due to increased pain or problems in the index knee and self-reported pain greater than 5 on a scale of 0 to 10 scale after an exercise session.
Self-reported Pain Before and After Exercise
Self-reported pain will be measured on a scale of 0 to 10. Pain will be monitored before class, in the end of the class, and 24 hours after class. Participants will record the pain score in their individual training diary before and after class. To record pain score 24 hours after class, a text message or an email (depending on participant's preference) containing a link to record the pain score will be sent using research electronic data capture (REDCap) software.
Major and Minor Adverse Events
Major and minor adverse events will be reported following the CONSORT extension statement for harms-reporting in randomized clinical trials. Major events are defined as death or hospitalization within trial care or 3 hours after. Minor events are defined as other unwanted outcomes that requires clinician attention.
Program Progression Achieved
Participants' progression during the 8-week exercise intervention will be recorded for each exercise station as the level of progression achieved in the end of the intervention. Four levels of progression are used (1-4).
Observed Exercise Fidelity
Observed exercise fidelity will be assessed using a checklist consisting of essential criteria for each exercise variation. Exercise fidelity will be expressed as percentage of exercise criteria achieved and will be recorded for each exercise as well as the complete program.
Measured Exercise Fidelity
Exercise fidelity during the group exercise sessions will be measured for all participants using inertial measurement units (IMUs). Measured exercise fidelity will be determined using a binary support vector machine classification model built to determine exercise fidelity for each exercise. Measured exercise fidelity will be expressed as percentage of exercise criteria achieved.
Average Heart Rate
Average heart rate (pbm) during the group exercise class measured using a heart rate monitor with a chest strap during the group exercise classes.
Maximum Heart Rate
Maximum heart rate (pbm) during the group exercise class measured using a heart rate monitor with a chest strap during the group exercise classes.
Time at Heart Rate Zone of 50 to 60 percent of HRmax
Time spent (as minutes) on heart rate zone of 50 to 60 percent of age-predicted maximum heart rate during the group exercise classes.
Time at Heart Rate Zone of 61 to 70 percent of HRmax
Time spent (as minutes) on heart rate zone of 61 to 70 percent of age-predicted maximum heart rate during the group exercise classes.
Time at Heart Rate Zone of 71 to 80 percent of HRmax
Time spent (as minutes) on heart rate zone of 71 to 80 percent of age-predicted maximum heart rate during the group exercise classes.
Time at Heart Rate Zone of 81 to 90 percent of HRmax
Time spent (as minutes) on heart rate zone of 81 to 90 percent of age-predicted maximum heart rate during the group exercise classes.
Time at Heart Rate Zone of >90 percent of HRmax
Time spent (as minutes) on heart rate zone of >90 percent of age-predicted maximum heart rate during the group exercise classes.
Knee Injury and Osteoarthritis Outcome Score (KOOS)
The KOOS consists of 42 items in five subscales: pain, other symptoms, function in daily living, function in sport and recreation, and knee related quality of life. Each item is scored on a 5-point Likert scale ranging from no problems to extreme problems. The subscale scores are summed, and the total score is transformed to a 0-100 scale with higher scores indicating better function.
Health-related Quality of Life (EQ-5D-5L)
The Canadian algorithm will be used to calculate the EuroQol 5 Dimension Questionnaire (EQ-5D-5L) score. The value set range for Canadians -0.148 (worst health status, worse than dead) to 0.949 (best health status).
Knee Self-efficacy (K-SES)
The K-SES covers four domains of self-efficacy: 1) daily activities (seven items), 2) sport and leisure activities (five items), 3) physical activities (six items), and 4) knee function in the future (four items). The response to the 22 items is given using an 11-grade Likert scale, ranging from 0 (not at all certain about the task) to 10 (very certain about the task). The sum of item scores is calculated and divided by the number of items. The total score is transformed to a 0-100 scale with higher score indicating better self-efficacy.
Intermittent and Constant Osteoarthritis Pain (ICOAP)
The ICOAP consists of 11 items forming two subscales. Each item was scored on a 5-point Likert scale ranging from no pain to high (disability-severely limiting) pain. Sub-scale scores will be summed and the total score transformed to a 1-100 scale (higher scores indicating poorer outcome).
Tampa Scale for Kinesiophobia (TSK)
The TSK consists of 17 items. Each item is scored on a 4-point Likert scale, ranging from 1 'strongly disagree' to 4 'strongly agree'. The range of total score is from 17 to 68. Higher scores indicate higher levels of kinesiophobia.
Healthcare Utilization
Healthcare utilization (i.e., visits to healthcare professionals, treatments, tests and services) will be based on participant self-report, on an item-by-item basis, for the 1-year period preceding testing. Current (2018) unit costs and rules from the Alberta Health Services Calgary Zone will be applied to value the health care system resources used by participants.
Knee Flexion Strength
Normalized knee flexion strength will be assessed at using hand-held isometric dynamometry. The peak isometric strength (N) scores are converted to torque values (Nm; force x distance between joint line and dynamometer position) and normalized to body weight (Nm/kg).
Hip Abduction Strength
Normalized hip abduction strength will be assessed at using hand-held isometric dynamometry. The peak isometric strength (N) scores are converted to torque values (Nm; force x distance between joint line and dynamometer position) and normalized to body weight (Nm/kg).
Hip Adduction Strength
Normalized hip adduction strength will be assessed at using hand-held isometric dynamometry. The peak isometric strength (N) scores are converted to torque values (Nm; force x distance between joint line and dynamometer position) and normalized to body weight (Nm/kg).
Triple Single-Leg Hop
Each participant will perform two trials of three consecutive single-leg hops with the goal of jumping as far as possible. Both legs will be tested (starting with the non-injured leg), and the maximum distance (cm) from the two trials normalized for leg length will be recorded for each leg.
Single-Leg Hop for Distance
The test will be performed until three successful trials have been recorded for both legs. Hop distance is measured in centimeters (cm) from the toe at the push-off to the heel where the subject landed. The maximum distance (cm) from the three trials normalized for leg length will be recorded for each leg.
Y-Balance Test
Three complete rounds on each leg will be completed with three reaching distances. The maximal reach distance (cm) at the point where the most distal part of the foot reaches is measured and normalized for lower extremity length. The normalised composite score will be calculated.
Moderate-to-vigorous Physical Activity
To determine the average daily minutes of moderate-to-vigorous PA (MVPA), all participants will wear a waist-mounted accelerometer device for seven days. Minutes of MVPA will be calculated based on activity corresponding to moderate activity 3-6 metabolic equivalents of task (MET) and vigorous activity >6 MET. A log will be used to record non-wear time (i.e. water-based activities) and activities with very limited vertical movement (i.e. spin class and cycling).
Asymmetries in Jumping Performance
Five inertial measurement units (Blue Trident IMU, Vicon Motion Systems Inc) will be attached to the body at the lower back, near the centre of mass and on the distal anteromedial aspect of each tibia. During the data collection participants will perform ten maximal countermovement jumps and ten maximal squat jumps with 30 second rest between jumps. Asymmetry in each phase will be reported as the difference between the left and right limb impulses divided by the maximum limb impulse and expressed as a percentage.
Fat mass index
Dual-energy x-ray absorptiometry (DXA) scanner will be used to capture whole body composition scans. Fat mass index will be calculated as fat mass relative to stature squared (kg/m^2).
Body mass index
Body mass index (BMI; kg/m^2) will be calculated from height (to the nearest 0.1 cm; shoes removed) and weight (to the nearest 0.1 kg) assessed using a medical scale and stadiometer.
Lean mass index
Dual-energy x-ray absorptiometry (DXA) scanner will be used to capture whole body composition scans. Lean mass index will be calculated as lean mass relative to stature squared (kg/m2).
Number of Exercise Sessions Completed during the Maintenance Stage
The total number of times the home exercise session was completed during the maintenance stage will be recorded.
Weekly Time Spent Completing the Program during the Maintenance Stage
The weekly minutes spent completing the home exercise sessions during the maintenance stage will be recorded.
Joint-specific Adverse Events during the Maintenance Stage
The number of joint-specific adverse events will be recorded during the maintenance stage. Joint-specific adverse events are determined as participant not attending an exercise session and/or ceasing participation due to increased pain or problems in the index knee and self-reported pain greater than 5 on a scale of 0 to 10 scale after an exercise session.
Consultations with the Study Physiotherapist during the Maintenance Stage
Total number of times the participants consulted the study physiotherapist during the maintenance stage to discuss their home exercise program.